Taurus

Taurus is a constellation in the northern hemisphere. Its name means "bull" in Latin. It is one of the constellations of the zodiac, listed by the Greek astronomer Ptolemy in the 2nd century.

The constellation Taurus is believed to have been identified with the bull since Chalcolithic times, and possibly even depicted at the Lascaux caves, along with the Pleiades cluster, around the year 15,000 BC. Babylonian astronomers called the constellation the Heavenly Bull. Ancient Egyptians believed that it represented a sacred bull, one associated with the renewal of nature in spring.

In Greek mythology, Taurus is associated with Zeus, who once disguised himself as a bull to abduct Europa, the daughter of King Agenor of Phoenicia. He carried her from Tyre across the sea to Crete. Their children included King Minos, famous for building the palace at Knossos.

The constellation Taurus occupies an area of 797 square degrees and contains three stars with known planets. It can be seen at latitudes between +90° and -65° and is best visible at 9 p.m. during the month of January. In tropical astrology, the Sun is said to be in Taurus between April 20 and May 21, while in sidereal astrology it passes through the sign from May 16 to June 15.

The brightest star in the constellation is [7931] alpha Tauri, or Aldebaran ("the follower"). Aldebaran is an orange-red giant, an irregular variable star, about 65 light-years distant. It is also sometimes called the Bull's Eye because it lies in the head of Taurus. It is the 13th brightest star in the sky. It was named Aldebaran because it appears to follow the Pleiades cluster across the sky. The Chinese know Aldebaran as the Fifth Star of the Net, while the Inuit call it the Spirit of the Polar Bear. The Seris people in Mexico believe that it provides light for seven women giving birth, represented by the Pleiades. The Dakotas saw the Pleiades as a white buffalo, chased by a hero (Aldebaran) across the sky.

[7932] beta Tauri, the second brightest star, lies near the border with the constellation Auriga. It is sometimes called El Nath or Alnath ("the bull’s horns"). El Nath is a B class star evolving into a giant. It lies about 131 light-years from Earth.

[7933] eta Tauri or Alcyone is the brightest of the Pleiades and the third brightest star in Taurus. It is a multiple star system with a blue-white giant for a primary component. Alcyone has an apparent magnitude of 2.85 and is approximately 440 light-years distant.

The Pleiades, also known as Messier 45 or the Seven Sisters, are a group of stars that form a young open cluster in Taurus. The Pleiades cluster is composed mostly of hot, blue, extremely luminous stars. It is the easiest cluster to find without the aid of binoculars. Lying about 440 light-years away, it is one of the nearest star clusters to Earth. It contains more than a thousand stars. The brightest nine are named after the Pleiades, the Seven Sisters in Greek mythology, and their parents, the titan Atlas and the sea-nymph Pleione. In the myth, Atlas was one of the titans who fought against Zeus and other Olympian gods and, once the titans were defeated, he was forced to carry the heavens on his shoulders as punishment. With Atlas out of the way, the hunter Orion started pursuing his daughters and Zeus turned them into stars to prevent Orion from catching them. The celestial Orion still follows the Pleiades across the sky.

[7939] Atlas is a multiple star system with a blue-white giant for a primary star. [7941] Electra is another blue-white giant. [7945] Maia is a blue giant classified as a mercury-manganese star. [7948] Merope is a blue-white subgiant classified as a Beta Cephei variable. [7957] Taygeta is another multiple system with a blue-white subgiant for the main component. [7983] Pleione is a blue-white dwarf classified as a Gamma Cassiopeiae type variable star. [8010] Celaeno is a blue-white subgiant, sometimes known as the Lost Pleiad because it cannot be easily distinguished from its brighter neighbour, [7939] Atlas. [8045] Asterope (Sterope) is a binary star with a blue-white dwarf for the brighter component.

There are several other notable stars in Taurus. [7934] zeta Tauri is a binary star 417 light-years distant. The primary component is an extremely luminous, hot, blue-white giant classified as a Gamma Cassiopeiae type variable. It has luminosity 5,700 times that of the Sun.

[7944]-[7935] theta Tauri is a star system, approximately 155 light-years distant, dominated by two bright, third magnitude giants, one orange and the other white.

[7936] lambda Tauri, or Elthor ("the bull") is a triple star system 370 light-years from Earth. The primary star is a blue-white dwarf and the companion is a white subgiant.

[7937] epsilon Tauri, also known as Ain ("eye") and Oculus Borealis ("northern eye"), is an orange giant, 147 light-years distant. It belongs to the Hyades cluster, the nearest open cluster to the solar system, lying only 151 light-years away. The Hyades cluster contains between 300 and 400 stars. The brightest ones form the shape of the letter V, which appears along the same line of sight as [7931] Aldebaran, a star that is not a member of the cluster.

[7940] gamma Tauri, or Hyadum I ("first Hyad") is another member of the Hyades cluster. It is a G class giant, 154 light-years distant.

Taurus contains the Crab Nebula (NGC 1952), the first Messier object ever to be listed. It is a pulsar wind nebula, which means that it is powered by the wind of a pulsar, found inside the shell of a supernova remnant. The Crab Pulsar, a rotating neutron star that emits gamma rays and radio waves, lies at the core of nebula. The Crab Nebula is approximately 6,500 light-years distant and expanding at the rate of 1,500 kilometres per second.